Reflector antennas are useful for a wide variety of applications. For example, reflector antennas are used in microwave relay linking, point to point communications, VSAT (very small aperture terminal) applications, and many other types of applications. In some instances, reflector antennas are used to track objects in the earth's orbitals (e.g., satellites) while in other instances dish antennas are used to track earth-side objects (e.g., vehicles or even missile trajectories).
In addition to the above applications, reflector antennas can be augmented to include monopulse tracking functionality. At a high level, monopulse tracking is a high precision target tracking technique. To achieve this high precision tracking, monopulse systems capture an incoming radiation signal and then measure that signal's arrival direction. To capture that signal, a monopulse system uses different quadrants of a feed horn array. The signal is then analyzed by a monopulse comparator network. In particular, the monopulse comparator network processes the return signals to generate a sum signal, two delta signals (Azimuth, Elevation), and a Q channel. These signals are then used to determine the direction of peak signal strength for the target. Accordingly, by using the antenna's feed horn array and the monopulse comparator network, a monopulse tracking system is able to precisely monitor and track a target's location and movement.
The monopulse comparator network discussed above is formed using several radio frequency (RF) building blocks. Some of these RF components include straight and rotational waveguides, hardware filtering components, hardware amplifier components, power splitters, and phase shifters. Notably, these RF building blocks are used to receive and manipulate the incoming radio waves to use for tracking the target. This same network also serves as the transmit path of the antenna via the sum port.
Receiving, transmitting, and manipulating radio waves are core functions of an antenna system (and a monopulse tracking system). Worthwhile to note, when unconfined, a radio wave will propagate in all three spatial dimensions. In other words, radio waves propagate as a spherical wave through space. Waveguides, which were briefly introduced above, have been developed to confine a radio wave's propagation. In particular, a waveguide is a metallic transmission line that restricts a radio wave so that it travels in only one direction. Waveguides are beneficial because even though they restrict a wave's propagation, the waveguide is structured so that the wave will not lose significant power. In order to redirect a radio wave, a waveguide must include walls that are completely reflective. Because of these reflective properties, the radio waves are routed through the waveguide in the desired direction.
Antennas, including monopulse tracking systems, use waveguides. In particular, an antenna uses a waveguide to transfer radio frequency energy between various portions of the antenna system. For instance, a waveguide may be used to connect an antenna to its transmitter or to its receiver. Furthermore, the monopulse comparator network, which was briefly discussed above, also uses waveguides when calculating the sum and delta signals.
While it is known how to design antennas that perform monopulse tracking, current designs are limited because they produce dish antennas that are bulky and difficult to work with. By way of example, current dish antenna designs physically mount the RF components on a rear portion of the dish antenna. As a result, there is not a lot of physical space behind the antenna to mount other hardware components. Furthermore, when hardware is mounted on the rear portion of the dish antenna, the antenna's center of gravity changes. As a result, it is necessary to reinforce and potentially even customize each antenna's mounting framework and direction control mechanisms. Accordingly, there is a substantial need to improve how a dish antenna is designed. Even more particularly, there is a substantial need to improve the design of antennas used for monopulse tracking.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those discussed above. Rather, this background is provided to illustrate only one exemplary technology area where some of the embodiments described herein may be practiced.